Islamic State jihadists have claimed responsibility for bomb blasts that killed more than 140 people in the Syiran towns of Jableh and Tartous, in the Assad regime's coastal heartland.

At least five suicide attackers managed to evade security, setting off car bombs at a petrol station in Tartous and a hospital and other primarily civilian targets in Jableh. Busy bus stations in both cities were hit.

People inspect the damage at the site of car bombing in a bus station in JablehCredit:
EPA/SANA

It has been spared the worst of the fighting in Syria's civil war, though young Alawite men have suffered greater losses proportionally than any other group. One estimate suggested more than a quarter of all Alawite men of fighting age had been killed.

Islamic State of Iraq and the Levant's main news outlet, Amaq, issued a single line statement said the group had attacked "gatherings of the Alawites". It regards the sect as heretical.

However, the coast has also become home to thousands of people of other sects fleeing the fighting elsewhere in the country.

Syrians gather at the site of multiple bombings in the northern coastal city of JablehCredit:
AFP/Getty Images

The bombings were confirmed by state media, though it gave a lower death toll than the 100 reported by the Syrian Observatory for Human Rights, the main overseas monitor.

Photographs posted online showed grim scenes, with bodies being carried away and the charred, twisted remains of buses and cars.

Tartous is the site of the main Russian naval base, part of a now growing chain of Russian military installations across the country.

The destroyed bus station in the northern coastal city of JablehCredit:
AFP/Getty Images

The Kremlin said the blasts showed the need to continue peace talks.

The United States and Russia have continued to discuss the meaning of the ceasefire theoretically in place across the country.

Russia and the regime bombed the outskirts of Aleppo heavily over the weekend, while the regime also attacked and retook part of the rebel-held enclave of Eastern Ghouta, near Damascus, following infighting between rebel groups there.

Russia says it is attacking groups allied to Jabhat al-Nusra, the al-Qaeda affiliate that is excluded from the terms of the ceasefire.